Responsible: Elise Nygård
E-mail: elisenyg@student.ibv.uio.no
Supervisors: Bente Edvardsen and Simon Hasselø Kline
Aim
The aim is to better understand the dynamics of the autumn phytoplankton bloom in the Oslofjord, both in the outer and inner part. Additionally, I aim to investigate if a more frequent sampling will reveal phytoplankton dynamics that are not discovered through monthly sampling. This sampling will be done through the ships-of -opportunity “Ferrybox” in cooperation with NIVA in combination with cruises onboard R/V Trygve Braarud.
Background
Increasing levels of man-made changes and climate change may potentially affect the species composition in phytoplankton communities (Opdal et al., 2019). Due to their significance in marine ecosystems and biogeochemical cycles, alterations in their composition can have far-reaching consequences (Biddanda et al., 2021; Caron et al., 2012). Temperate regions are characterized by significant seasonal variations in light, temperature, and weather patterns (Pratolongo et al., 2019). In temperate marine areas, such as in southern Norway, there are often two blooms of phytoplankton, one in the spring and one in the autumn (Lundsør et al., 2020).
The autumn bloom is less extensive than the spring bloom and is therefore less studied than the spring bloom. This makes it even more important to conduct research on the phytoplankton autumn blooms. Due to differences in temperature, light conditions, and nutrient availability, the two distinct blooming events will include different species (Carstensen et al., 2015).
Monitoring programs of protist communities traditionally collect samples once a month (Lundsør et al., 2020). Phytoplankton grow quickly and can under good conditions (enough light, nutrition and the right temperature) more than double the number of cells in a day (Eppley, 1972). This means that one cannot exclude that one excludes parts of the aspect of population dynamics and species composition between the monthly samplings, especially during the spring and autumn bloom where conditions are most optimal, and growth at its greatest.
While we are studying the Oslofjord and using that as our study region, this thesis can help our understanding of phytoplankton communities in temperate regions in general.
Research Questions
- What is the taxonomic composition and dynamics of the protist community during the autumn bloom in the Oslofjord seen through metabarcoding?
- Do we see a difference in alfa- and beta-diversity between the two stations, the outer (station OF2) and the inner Oslofjord (station DK1)?
- Do we see any differences in the community composition between the years 2023 and 2024?
- Do we see any differences in the community composition with monthly sampling vs a more intensive sampling approach?
- Which environmental factors can explain some of the differences in time and space?
This project will hopefully provide insights into the dynamics of phytoplankton during the autumn bloom in the Oslofjord. It will assess how intensive sampling can reveal dynamics that are not captured by the current monthly sampling approach.